Does mtrace() still work in modern distros?

tldr: Does mtrace still work or am I just doing it wrong?

I was attempting to use mtrace and have been unable to get it to write data to a file. I followed the instructions in man 3 mtrace:

t_mtrace.c:

#include <mcheck.h>
#include <stdlib.h>
#include <stdio.h>

int
main(int argc, char *argv[])
{
    mtrace();

    for (int j = 0; j < 2; j++)
        malloc(100);            /* Never freed--a memory leak */

    calloc(16, 16);             /* Never freed--a memory leak */
    exit(EXIT_SUCCESS);
}

Then running this in bash:

gcc -g t_mtrace.c -O0 -o t_mtrace
export MALLOC_TRACE=/tmp/t
./t_mtrace
mtrace ./t_mtrace $MALLOC_TRACE

but the file /tmp/t (or any other file I attempt to use) is not created. When I create an empty file with that name it remains zero length. I’ve tried using relative paths in the MALLOC_TRACE. I tried adding setenv("MALLOC_TRACE", "/tmp/t", 1); inside the program before the mtrace() call. I’ve tried adding muntrace() before the program terminates. I’ve tried these tactics on Ubuntu 22.04 and Fedora 39, and I get the same result: the trace file is empty. The ctime and mtime on the file (if I create it in advance) are unchanged when I run the program. I’ve verified the permissions of the file and its parent directory are read/writable. strace isn’t showing that the file in question is stated, much less opened.

This occurs using Glibc 2.35 on Ubuntu and 2.38 on Fedora.

This isn’t a question on how to profile or check for memory leaks. I realize I can do this with valgrind or half a dozen other programs, this is mostly a curiosity and me wanting to know if this is a bug that might need to be patched or whether the man page needs updating (or whether I’m just misapprehending something and the only problem is sitting in my chair).